The invention relates to a method and equipment for cleaning greenhouse roofs made of plastic sheets. For the growing of greenhouse crops the most important factor for their development is the amount of sunlight radiated upon them. That is why low light transparency of the covering material is of paramount Importance. The most important factor is the selection of the type of material covering the greenhouse roof. In the market there are different kinds of covering materials of various types which are divided in to two groups: the first one is rigid, for example, Glass and plastic plates like polycarbonate. The second group is flexible (soft) covering materials of plastic sheets such as PVC and polyethylene.
The most popular and most extensively used covering in Israel is the soft plastic sheeting. The roofs accumulate large quantities of dust, which prevent the transfer of light into the greenhouse and retard the development rates of the produce and delay the ripening process. Reduction of light transfer has a negative effect on the size of the fruit, plants produce est. With certain types of flowers the time between blooming of the flowers found to be longer.
Many researches investigated the effect of light transfer in greenhouses on plant development. It was found that after regular cleaning of the greenhouse's roof during the growth of the produce, the result was 30% increase of produce, increase of fruit size and quality and flowers with longer stems. It also shortens the time between each blooming and in general a greater number of stems and branches was found per plant. This data has a great economic influence on agriculture. Where by the use of a given area and amount of water, there is an increase in quantity and quality of the produce by a factor up to 30%. This is a major achievement. At present, some farmers in Israel confront these problems by manual and expensive washing, which is time consuming and made when the workers are free from other work in the greenhouse. For this reason greenhouse roofs are rarely cleaned, just once or twice per growth season, which is definitely not enough. There is a great advantage to be gained by the regular and periodic cleaning of the greenhouse roof. The preferred solution is to clean it by mechanical and automation means.
On the market there is a wide range of greenhouses of different dimensions: width, height, length est. some are characterized by different roof cross section e.g. symmetrical or asymmetrical. At the present moment there do not exist roof cleaning devices that answer to these conditions, although VIKA company produce a cleaning machine for glass greenhouses with one uniform shape.
It is an object of the invention to provide a method and apparatus for cleaning soft plastic sheeting roofs automatically.